Intraoperative Assessment of Facial Nerve Trunk Width in Early Childhood With Cervicofacial Lymphatic Malformation

BACKGROUND Facial nerve damage during head and neck surgery has long been an important issue. However, few publications on the gross anatomy of the facial nerve are available in the young population. The aim of this study was to provide in vivo measurements of the facial nerve trunk during lymphatic malformation (LM) resection and to determine the association between the trunk width and patient- and disease-related variables. METHODS We conducted a retrospective analysis of 11 consecutive pediatric patients (11 facial nerve trunks) who underwent cervicofacial LM resection. The facial nerve of the affected side was dissected, and its trunk width at bifurcation was measured using calipers under a microscope during the operation. RESULTS Eleven patients younger than 6 years were enrolled. The median width of the facial nerve in patients younger than 1 year was 1.15 mm; it was 2.5 mm in those older than 1 year. Trunk width was significantly greater in patients older than 1 year than those younger than 1 year, whereas no statistical significance was found when comparing other age groups. Patient weight was positively correlated with trunk width, whereas LM grade and diameter showed no significant correlation. CONCLUSIONS The significantly greater width of the facial nerve trunk in LM patients older than 1 year than those younger than 1 year suggests that the age of 1 may be a threshold for facial nerve hypertrophy and growth acceleration. This study provides informative in vivo data to help understand facial nerve characteristics in young patients.